Luminescence properties and application of lanthanide doped nano- and micro-sized upconversion and downshifting materials

Trivalent lanthanide ions show interesting luminescence properties due to the optical transitions within the 4fn electronic manifold. A consequence of the shielding of the f electrons is that their f-f emission spectra consist of sharp narrow lines, which creates the possibility of using rare-earth ions as effective and efficient luminescent centers. The introduction of lanthanides into different matrix leads to many promising applications, such as lighting, 3D display, sensors, battery devices and biology application. There are several types of luminescence conversions: upconversion, downconversion and downshifting. Downshifting is the process when a photon with higher energy is converted into one photon of lower energy, while upconversion is the adverse process, where at least two lower-energy photons are “added up” to obtain one higher-energy photon. Here, we introduce some of our work towards different applications by taking advantage of the introduction of different lanthanides into various matrix. There are three main parts of our work, dual-mode upconversion and downshifting material towards white light emission, downshifting/upconversion luminescent materials as highly sensitive fluorescent sensors for Pb2+ ions detection and luminescent nanosheets for optical thermometry. We relate different methods to combine upconversion and downshifting to achieve the dual-mode white light emission. We also compared NaY(MoO4)2 downshifting material with upconversion material, the later one shows better a highly selective “turn on” fluorescent sensor for Pb2+ ions. For the incorporation of Eu ions into MoS2 2D nanosheets, it can show good optical thermometric sensing performance. References [1] J. Liu, A. M. Kaczmarek and R. Van Deun, Journal of Luminescence, 2017, 188, 604-611. [2] J. Liu, R. Van Deun and A. M. Kaczmarek, J. Mater. Chem. C, 2016, 4, 9937-9941.